Internet addiction has for the first time been linked with changes in the brain similar to those seen in people addicted to alcohol, cocaine and cannabis. In a groundbreaking study, researchers used MRI scanners to reveal abnormalities in the brains of adolescents who spent many hours on the internet, to the detriment of their social and personal lives. The finding could throw light on other behavioural problems and lead to the development of new approaches to treatment, researchers said.

An estimated 5 to 10 per cent of internet users are thought to be addicted – meaning they are unable to control their use. The majority are games players who become so absorbed in the activity they go without food or drink for long periods and their education, work and relationships suffer.

Henrietta Bowden Jones, consultant psychiatrist at Imperial College, London, who runs Britain’s only NHS clinic for internet addicts and problem gamblers, said: “The majority of people we see with serious internet addiction are gamers – people who spend long hours in roles in various games that cause them to disregard their obligations. I have seen people who stopped attending university lectures, failed their degrees or their marriages broke down because they were unable to emotionally connect with anything outside the game.”

Although most of the population was spending longer online, that was not evidence of addiction, she said. “It is different. We are doing it because modern life requires us to link up over the net in regard to jobs, professional and social connections – but not in an obsessive way. When someone comes to you and says they did not sleep last night because they spent 14 hours playing games, and it was the same the previous night, and they tried to stop but they couldn’t – you know they have a problem. It does tend to be the gaming that catches people out.”